Guardrails provide significant safety advantages, namely protecting errant vehicles from leaving the roadway and/or from various roadside hazards. For proper functioning, the guardrails are positioned at a height sufficient to safely redirect the errant vehicle, without the vehicle rolling over the top of, or diving under, the guardrail. While the guardrail may assume various cross-sectional shapes and configurations, one typical configuration is a “W” beam, with the shape and materials governed by the AASHTO M-180 Guardrail Specification. One problem with such guardrail systems is presented at the end of a section thereof, wherein a conventional guardrail section may present a spearing hazard to a vehicle impacting the end of the guardrail in a head-on collation.
In response, various solutions have been introduced, including turning down (twisting and anchoring) the end of the guardrail to ground level, which may lead to vehicles being vaulted into the air. Other solutions include providing for breakaway post systems, with the guardrails buckling or sliding past each other as one or more support posts are broken during an axial impact event. In other systems, the guardrail is both deformed and laterally deflected, thereby absorbing energy while also eliminating the spearing hazard. In yet another type of system, a deforming device is provided at the impact end of the guardrail, as shown in U.S. Pat. No. 6,719,483 to Welandsson and U.S. Pat. No. 7,694,941 to Abu-Odeh. In these types of systems, the deforming device deforms the guardrail and directs/transitions the guardrail downwardly and then horizontally at ground level, bending the guardrail in two different rotational directions, including one at ground level, during the impact sequence. As such, the devices may be difficult to set up, requiring a threading of a draw member, whether configured as a cable or a flattened portion of the guardrail, through the redirecting channel or tube of device. In addition to the added cost associated with the assembly and set up, the elaborately shaped deforming devices require additional materials and assembly costs.
Thus, the need remains for a low cost guardrail end terminal that dissipates the energy of an impacting vehicle, while reducing the risk of spearing.